For the compound potassium sulfate, K2SO4, what is the electron configuration of the potassium ion? [Ar]4s1 How many atoms will be contained in one mole of potassium sulfate? There will be 7 atoms in one mole of potassium sulfate. What is the percentage composition by weight of oxygen in potassium sulfate? The percentage composition by weight of oxygen in potassium sulfate is 48.38%. 13. Draw a Lewis dot diagram for the carbonate ion, CO3^2-, and predict its bond angle and molecular shape.
The Correct Answer and Explanation is:
Electron Configuration of the Potassium Ion (K⁺):
The electron configuration for neutral potassium (K) is:
K: [Ar]4s1\text{K: [Ar]} 4s^1K: [Ar]4s1
When potassium loses one electron to form a K⁺ ion, the electron configuration changes. The resulting configuration for K⁺ becomes:
K+:[Ar]\text{K}^+: \text{[Ar]}K+:[Ar]
This is because potassium has lost its one valence electron in the 4s orbital, leaving it with the same electron configuration as the noble gas argon.
2. Number of Atoms in One Mole of Potassium Sulfate (K₂SO₄):
To calculate the number of atoms in one mole of potassium sulfate (K₂SO₄), we need to consider the formula and the number of atoms in each element. Potassium sulfate contains:
- 2 potassium (K) atoms
- 1 sulfur (S) atom
- 4 oxygen (O) atoms
In total, the number of atoms in one formula unit of K₂SO₄ is:
2 (K)+1 (S)+4 (O)=7 atoms2 \, (\text{K}) + 1 \, (\text{S}) + 4 \, (\text{O}) = 7 \, \text{atoms}2(K)+1(S)+4(O)=7atoms
Thus, one mole of potassium sulfate will contain 7 atoms in total.
3. Percentage Composition by Weight of Oxygen in Potassium Sulfate:
To calculate the percentage by weight of oxygen in K₂SO₄, we need to determine the molar mass of each component in the compound.
- The molar mass of potassium (K) is approximately 39.10 g/mol.
- The molar mass of sulfur (S) is approximately 32.07 g/mol.
- The molar mass of oxygen (O) is approximately 16.00 g/mol.
The molar mass of K₂SO₄ is: Molar mass of K₂SO₄=(2×39.10)+32.07+(4×16.00)=78.20+32.07+64.00=174.27 g/mol\text{Molar mass of K₂SO₄} = (2 \times 39.10) + 32.07 + (4 \times 16.00) = 78.20 + 32.07 + 64.00 = 174.27 \, \text{g/mol}Molar mass of K₂SO₄=(2×39.10)+32.07+(4×16.00)=78.20+32.07+64.00=174.27g/mol
Now, the total mass of oxygen in K₂SO₄ is: Mass of O=4×16.00=64.00 g/mol\text{Mass of O} = 4 \times 16.00 = 64.00 \, \text{g/mol}Mass of O=4×16.00=64.00g/mol
The percentage composition by weight of oxygen is: Percentage of O=64.00174.27×100=36.7%\text{Percentage of O} = \frac{64.00}{174.27} \times 100 = 36.7\%Percentage of O=174.2764.00×100=36.7%
Therefore, the percentage composition by weight of oxygen in potassium sulfate is approximately 36.7% (not 48.38%).
4. Lewis Dot Diagram for the Carbonate Ion (CO₃²⁻):
The carbonate ion (CO₃²⁻) consists of one carbon (C) atom bonded to three oxygen (O) atoms. Since the ion has a 2- charge, it means there are two extra electrons. Let’s break down the steps to draw the Lewis dot structure:
- Carbon (C) is in Group 14, so it has 4 valence electrons.
- Each oxygen (O) is in Group 16 and has 6 valence electrons. Since there are 3 oxygen atoms, this gives 3×6=183 \times 6 = 183×6=18 valence electrons.
- The 2- charge indicates 2 extra electrons.
Thus, the total number of valence electrons is: 4(from C)+18(from O)+2(extra electrons from charge)=24 electrons4 (\text{from C}) + 18 (\text{from O}) + 2 (\text{extra electrons from charge}) = 24 \, \text{electrons}4(from C)+18(from O)+2(extra electrons from charge)=24electrons
To arrange the electrons:
- Carbon is in the center, and the three oxygen atoms are arranged symmetrically around it.
- Each oxygen atom forms a double bond with carbon, and one of the oxygen atoms forms a single bond with a negative charge.
- The electron pairs are arranged to minimize repulsion and make the structure stable.
The bond angle in the carbonate ion is 120°, as it has a trigonal planar molecular shape, meaning the three atoms are arranged in a flat, triangular shape around the central carbon.
Molecular Shape: Trigonal Planar
Bond Angle: 120°
